This invention relates to a metal cutting machine with cut piece pickup and transport magnets.
Metal cutting machines using flame cutting torches or the like have long been known for cutting a plurality of relatively small pieces from a large metal plate. See, for example, U.S. Pat. Nos. 3,866,892 and 4,012,027. Such machines may utilize the well-known numerical control, photoelectric tracers and the like for controlling the movement of the cutting heads.
Subsequent to cutting, the cut pieces must be removed from the plate and transported to another location.
The cut pieces are usually of very heavy steel and may range in weight from about 4-5 pounds to several hundred pounds each. The pieces are usually too heavy for an operator to manually handle.
It is known to remove cut pieces one-at-a-time from the skeletal plate by use of an overhead crane from which an electromagnet is suspended. The U.S. Pat. No. 675,323 is illustrative of a crane type magnetic device.
It is furthermore known to utilize an electromagnet in a metal cutting machine for holding a part of a workpiece in place while a torch cuts the piece out by moving around the periphery of the magnet, as in U.S. Pat. No. 2,363,007.
Additionally, it is known to use electromagnets for picking up and transporting large metal objects in breaking up large ships and the like, as in U.S. Pat. No. 4,139,180. Furthermore, magnets are used for transport of stacks of cans, as in U.S. Pat. No. 2,729,344, and in other material handling devices such as in U.S. Pat. No. 3,856,157.
It is a task of the present invention to provide a multiple-piece type metal cutting machine having thereon a simple, yet effective means for removing one or a plurality of previously cut pieces from the skeletal workpiece and for transporting the pieces to a suitable receiving station.
It is a further task of the invention to provide selectivity as to which cut piece or pieces are to be handled at any given time in the overall process of removing all the cut pieces from the skeletal workpiece.
The invention is contemplated for use in a metal cutting machine having a plurality of tool carrying cutting heads mounted for movement along a bridge which in turn is mounted on rails or the like for movement transverse to the direction of head movement. Controls are provided for selective movement of the heads and bridge.
A bridge-mounted plurality of magnet assemblies are provided which, after one or more cut pieces have been formed from a plate-like workpiece by the heads, are actuated to engage the cut pieces and raise them from the remaining skeletal workpiece. The bridge on which the magnet assemblies are mounted is movable to a position remote from the workpiece so that the magnets can deposit the cut pieces at a receiving point.
It is contemplated that the assemblies may be mounted on the same bridge as the cutting heads and connected to the latter for selective horizontal positioning by the same controls used for cutting. Alternately, the assemblies may be mounted on a separate bridge disposed on the same rails.